From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 30 Jun 2023 13:11:51 +0200
Subject: [PATCH] mac80211: split mesh fast tx cache into
 local/proxied/forwarded

Depending on the origin of the packets (and their SA), 802.11 + mesh headers
could be filled in differently. In order to properly deal with that, add a
new field to the lookup key, indicating the type (local, proxied or
forwarded). This can fix spurious packet drop issues that depend on the order
in which nodes/hosts communicate with each other.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -765,6 +765,9 @@ bool ieee80211_mesh_xmit_fast(struct iee
 			      struct sk_buff *skb, u32 ctrl_flags)
 {
 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct ieee80211_mesh_fast_tx_key key = {
+		.type = MESH_FAST_TX_TYPE_LOCAL
+	};
 	struct ieee80211_mesh_fast_tx *entry;
 	struct ieee80211s_hdr *meshhdr;
 	u8 sa[ETH_ALEN] __aligned(2);
@@ -800,7 +803,10 @@ bool ieee80211_mesh_xmit_fast(struct iee
 			return false;
 	}
 
-	entry = mesh_fast_tx_get(sdata, skb->data);
+	ether_addr_copy(key.addr, skb->data);
+	if (!ether_addr_equal(skb->data + ETH_ALEN, sdata->vif.addr))
+		key.type = MESH_FAST_TX_TYPE_PROXIED;
+	entry = mesh_fast_tx_get(sdata, &key);
 	if (!entry)
 		return false;
 
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -134,9 +134,33 @@ struct mesh_path {
 #define MESH_FAST_TX_CACHE_TIMEOUT		8000 /* msecs */
 
 /**
+ * enum ieee80211_mesh_fast_tx_type - cached mesh fast tx entry type
+ *
+ * @MESH_FAST_TX_TYPE_LOCAL: tx from the local vif address as SA
+ * @MESH_FAST_TX_TYPE_PROXIED: local tx with a different SA (e.g. bridged)
+ * @MESH_FAST_TX_TYPE_FORWARDED: forwarded from a different mesh point
+ */
+enum ieee80211_mesh_fast_tx_type {
+	MESH_FAST_TX_TYPE_LOCAL,
+	MESH_FAST_TX_TYPE_PROXIED,
+	MESH_FAST_TX_TYPE_FORWARDED,
+};
+
+/**
+ * struct ieee80211_mesh_fast_tx_key - cached mesh fast tx entry key
+ *
+ * @addr: The Ethernet DA for this entry
+ * @type: cache entry type
+ */
+struct ieee80211_mesh_fast_tx_key {
+	u8 addr[ETH_ALEN] __aligned(2);
+	enum ieee80211_mesh_fast_tx_type type;
+};
+
+/**
  * struct ieee80211_mesh_fast_tx - cached mesh fast tx entry
  * @rhash: rhashtable pointer
- * @addr_key: The Ethernet DA which is the key for this entry
+ * @key: the lookup key for this cache entry
  * @fast_tx: base fast_tx data
  * @hdr: cached mesh and rfc1042 headers
  * @hdrlen: length of mesh + rfc1042
@@ -147,7 +171,7 @@ struct mesh_path {
  */
 struct ieee80211_mesh_fast_tx {
 	struct rhash_head rhash;
-	u8 addr_key[ETH_ALEN] __aligned(2);
+	struct ieee80211_mesh_fast_tx_key key;
 
 	struct ieee80211_fast_tx fast_tx;
 	u8 hdr[sizeof(struct ieee80211s_hdr) + sizeof(rfc1042_header)];
@@ -334,7 +358,8 @@ void mesh_path_tx_root_frame(struct ieee
 
 bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt);
 struct ieee80211_mesh_fast_tx *
-mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata, const u8 *addr);
+mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_mesh_fast_tx_key *key);
 bool ieee80211_mesh_xmit_fast(struct ieee80211_sub_if_data *sdata,
 			      struct sk_buff *skb, u32 ctrl_flags);
 void mesh_fast_tx_cache(struct ieee80211_sub_if_data *sdata,
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -36,8 +36,8 @@ static const struct rhashtable_params me
 static const struct rhashtable_params fast_tx_rht_params = {
 	.nelem_hint = 10,
 	.automatic_shrinking = true,
-	.key_len = ETH_ALEN,
-	.key_offset = offsetof(struct ieee80211_mesh_fast_tx, addr_key),
+	.key_len = sizeof(struct ieee80211_mesh_fast_tx_key),
+	.key_offset = offsetof(struct ieee80211_mesh_fast_tx, key),
 	.head_offset = offsetof(struct ieee80211_mesh_fast_tx, rhash),
 	.hashfn = mesh_table_hash,
 };
@@ -426,20 +426,21 @@ static void mesh_fast_tx_entry_free(stru
 }
 
 struct ieee80211_mesh_fast_tx *
-mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata, const u8 *addr)
+mesh_fast_tx_get(struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_mesh_fast_tx_key *key)
 {
 	struct ieee80211_mesh_fast_tx *entry;
 	struct mesh_tx_cache *cache;
 
 	cache = &sdata->u.mesh.tx_cache;
-	entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
+	entry = rhashtable_lookup(&cache->rht, key, fast_tx_rht_params);
 	if (!entry)
 		return NULL;
 
 	if (!(entry->mpath->flags & MESH_PATH_ACTIVE) ||
 	    mpath_expired(entry->mpath)) {
 		spin_lock_bh(&cache->walk_lock);
-		entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
+		entry = rhashtable_lookup(&cache->rht, key, fast_tx_rht_params);
 		if (entry)
 		    mesh_fast_tx_entry_free(cache, entry);
 		spin_unlock_bh(&cache->walk_lock);
@@ -484,18 +485,24 @@ void mesh_fast_tx_cache(struct ieee80211
 	if (!sta)
 		return;
 
+	build.key.type = MESH_FAST_TX_TYPE_LOCAL;
 	if ((meshhdr->flags & MESH_FLAGS_AE) == MESH_FLAGS_AE_A5_A6) {
 		/* This is required to keep the mppath alive */
 		mppath = mpp_path_lookup(sdata, meshhdr->eaddr1);
 		if (!mppath)
 			return;
 		build.mppath = mppath;
+		if (!ether_addr_equal(meshhdr->eaddr2, sdata->vif.addr))
+			build.key.type = MESH_FAST_TX_TYPE_PROXIED;
 	} else if (ieee80211_has_a4(hdr->frame_control)) {
 		mppath = mpath;
 	} else {
 		return;
 	}
 
+	if (!ether_addr_equal(hdr->addr4, sdata->vif.addr))
+		build.key.type = MESH_FAST_TX_TYPE_FORWARDED;
+
 	/* rate limit, in case fast xmit can't be enabled */
 	if (mppath->fast_tx_check == jiffies)
 		return;
@@ -542,7 +549,7 @@ void mesh_fast_tx_cache(struct ieee80211
 		}
 	}
 
-	memcpy(build.addr_key, mppath->dst, ETH_ALEN);
+	memcpy(build.key.addr, mppath->dst, ETH_ALEN);
 	build.timestamp = jiffies;
 	build.fast_tx.band = info->band;
 	build.fast_tx.da_offs = offsetof(struct ieee80211_hdr, addr3);
@@ -644,13 +651,19 @@ void mesh_fast_tx_flush_addr(struct ieee
 			     const u8 *addr)
 {
 	struct mesh_tx_cache *cache = &sdata->u.mesh.tx_cache;
+	struct ieee80211_mesh_fast_tx_key key = {};
 	struct ieee80211_mesh_fast_tx *entry;
+	int i;
 
+	ether_addr_copy(key.addr, addr);
 	cache = &sdata->u.mesh.tx_cache;
 	spin_lock_bh(&cache->walk_lock);
-	entry = rhashtable_lookup(&cache->rht, addr, fast_tx_rht_params);
-	if (entry)
-		mesh_fast_tx_entry_free(cache, entry);
+	for (i = MESH_FAST_TX_TYPE_LOCAL; i < MESH_FAST_TX_TYPE_FORWARDED; i++) {
+		key.type = i;
+		entry = rhashtable_lookup(&cache->rht, &key, fast_tx_rht_params);
+		if (entry)
+			mesh_fast_tx_entry_free(cache, entry);
+	}
 	spin_unlock_bh(&cache->walk_lock);
 }
 
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2727,7 +2727,10 @@ ieee80211_rx_mesh_fast_forward(struct ie
 			       struct sk_buff *skb, int hdrlen)
 {
 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
-	struct ieee80211_mesh_fast_tx *entry = NULL;
+	struct ieee80211_mesh_fast_tx_key key = {
+		.type = MESH_FAST_TX_TYPE_FORWARDED
+	};
+	struct ieee80211_mesh_fast_tx *entry;
 	struct ieee80211s_hdr *mesh_hdr;
 	struct tid_ampdu_tx *tid_tx;
 	struct sta_info *sta;
@@ -2736,9 +2739,13 @@ ieee80211_rx_mesh_fast_forward(struct ie
 
 	mesh_hdr = (struct ieee80211s_hdr *)(skb->data + sizeof(eth));
 	if ((mesh_hdr->flags & MESH_FLAGS_AE) == MESH_FLAGS_AE_A5_A6)
-		entry = mesh_fast_tx_get(sdata, mesh_hdr->eaddr1);
+		ether_addr_copy(key.addr, mesh_hdr->eaddr1);
 	else if (!(mesh_hdr->flags & MESH_FLAGS_AE))
-		entry = mesh_fast_tx_get(sdata, skb->data);
+		ether_addr_copy(key.addr, skb->data);
+	else
+		return false;
+
+	entry = mesh_fast_tx_get(sdata, &key);
 	if (!entry)
 		return false;
 
